Guinea Pig Maximization Test (GPMT)

A big variety of chemical components such as starting materials and processing aids including lubricants and mould-release agents used in the manufacture of medical device, adhesive/solvent residues from assembly process, and sterilant residues from sterilization process may be present in a finished product. It shall be taken into consideration that whether these components have the potential sensitization activity.

The guinea pig maximization test is designed to evaluate the contact dermal sensitization caused by repeated skin exposure to the extract from medical device.

STEMart offers in vivo guinea pig maximization test for skin sensitizing potential investigation according to the biocompatibility guidelines modified for medical devices.

Standard of GPMT

• ISO 10993-10: 2010
• OECD No. 406

Test Principle of GPMT

Expose the test animals to the test substance by intradermal injection and/or epidermal application. Following an induction period, which allows for the development of an immune response, expose the animals to a challenge dose. Compare the extent and degree of skin reaction to the challenge exposure in the test animals with that demonstrated by control animals which are sham treated during induction and receive the challenge exposure.

Test Animal for GPMT

Guinea pig

Test Procedure

• Intradermal injection induction phase

Make three pairs of 0.1 ml intradermal injections into each animal.

• Topical application induction phase

With the filter paper patch or absorbent gauze fully loaded with the test substance, administer the test substance by topical application to the intrascapular region of test animals at 7 ± 1 days after completion of the intradermal injection induction phase. Control animals receive the same treatment, except that the appropriate solvent/vehicle is used instead of the test article. Remove the patches and dressings after 48 ± 2 hours.

• Challenge phase

Challenge all test and control animals with filter paper patches or chambers soaked in the test substance at 14 ± 1 days after completion of the topical induction phase.

• Observation of animals

Examine the formation of erythema and edema in the application sites at approximately 24, 48, and 72 hours after removing the challenge patches.

• Result interpretation

Positive results:

• Grades of less than 1 in control group: grades of 1 or greater are noted in the test group;
• Grades of 1 or greater in control group: the response of test animals exceed the most severe reaction in control animals.

Rechallenge recommended

• The response of animals is equivocal;
• The number of animals showing a response in test group is greater than that in control group, while the reaction intensity is note greater than that exhibited by the controls.

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References

• International Organization for Standardization. Biological evaluation of medical devices — Part 10: Selection of tests for interactions with blood. ISO 10993-10; (2010).
• OECD Guideline for Testing of Chemicals. No 406 Skin Sensitization (1992).